//保存cookie
function _addCookie(cookie){
    document.cookie = cookie;
}

//导出照片
function _exportRaw(name, data) {
  var urlObject = window.URL || window.webkitURL || window;
  var export_blob = new Blob([data]);
  var save_link = document.createElementNS("http://www.w3.org/1999/xhtml", "a")
  save_link.href = urlObject.createObjectURL(export_blob);
  save_link.download = name;
  fake_click(save_link);
}

//模拟点击事件
function fake_click(obj) {
  var ev = document.createEvent("MouseEvents");
  ev.initMouseEvent(
      "click", true, false, window, 0, 0, 0, 0, 0
      , false, false, false, false, 0, null
      );
  obj.dispatchEvent(ev);
}